How common is it for the valve stem seals to be a major source of oil burn?
My understanding on these diesels, especially the turbo-diesels, is 'not very'. The turbos run with positive manifold pressure a good portion of the time, which means that the prevailing winds (so to speak) are pushing back out the valve stems, not sucking in as is the case for NA engines.
But it _can_ happen that they leak enough to cause oil consumption, or so I also am led to understand. -- Jim
